发明名称 |
APPARATUS AND METHOD FOR SUPERVISING DERIVED CHANNEL COMMUNICATIONS |
摘要 |
A supervisory signal (18) for a derived channel data reporting system is implemented as a tone having a frequency capable of transmission using a telephone signal communicating network (31), including networks incorporating digital equipment, at an attenuated level. The tone preferably has a frequency of from 200 Hz to 300 Hz, and is capable of operating in conjunction with biphase modulated (BPSK), frequency shift keyed (FSK) and multi-tone modulated (MLT) polling systems. Such frequencies are effectively communicated by conventional digital loop carrier systems, despite a limited frequency range, and are of a sufficient magnitude to be detected by the derived channel data reporting system.
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申请公布号 |
WO9735418(A1) |
申请公布日期 |
1997.09.25 |
申请号 |
WO1997US04342 |
申请日期 |
1997.03.19 |
申请人 |
NUMEREX INVESTMENT CORPORATION |
发明人 |
JEHNERT, WALT;HUGHEY, STEPHEN, A.;EAKES, JAMES, W.;DARR, ROGER, RAYMOND |
分类号 |
H04M11/00;H04M11/04;H04M11/06;(IPC1-7):H04M11/04 |
主分类号 |
H04M11/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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